Vancomycin or metronidazole in the outpatient treatment of mild-moderate Clostridioides difficile infection

Background: : Recommended treatment against mild cases of Clostridioides difficile associated diarrhea is vancomycin despite the difficulties of access compared to metronidazole. Aim: : To compare the effectiveness of vancomycin and metronidazole in Chilean adults with first mild-moderate episode of Clostridiodes difficile infection (CDI). Methods: Retrospective cohort of patients with CDI between January 2015 and December 2020 treated in centers of a university health network. The patients were adults treated for C. difficile infection on an outpatient basis. Recurrent and severe cases were excluded. Outcomes included clinical cure and recurrence rate. Results: : Data from 161 patients was recovered. Fifty-nine percent were women and average age was 53 (18-94). One hundred and nine patients were treated with metronidazole (67.7%) and 52 (32.3%) used vancomycin. Multivariate analysis adjusted by age and comorbidities showed an Odds Ratio of 3.00 (IC 95% 1.12-9.59) for clinical cure and 0.27 (IC 95% 0.06-0.88) for 8-week recurrence rate, both in favor of vancomycin, without differences in 12-month recurrence rate, hospitalization rate nor mortality. Conclusions: Vancomycin is associated with better short-term outcomes in the treatment of outpatient mild-moderate first episode C. difficile infection, without differences in long term recurrence or mortality when compared with metronidazole.